In the manufacture of printed circuit boards, printed circuit elements and like goods, and in processes connected with the same, it has become commonplace to deliver the articles, such as printed circuit boards, printed circuit film or the like, through a chamber in a continuous manner, while the articles are being treated by the spray of a suitable treatment fluid, such as an etchant, onto them. Often the etchant is of a corrosive nature, but on other occasions it can be various chemical solutions or even ordinary rinsing liquid, such as water. See, for example, U.S. Pat. No. 4,233,106, the disclosure of which is herein incorporated by reference.
In the course of treatment of articles, such as printed circuit boards and the like, it has become commonplace to supply the treatment liquid via orifices in the form of spray heads, nozzles, flood bars and the like, which spray or impinge the treatment liquid upon the articles as they pass the zone of spray emanating from such orifices. In some instances, the printed circuit boards pass in a generally horizontal path of travel, preferably while being in horizontal orientation, and often have the treatment fluid applied from both above and below while the articles are moving along their path of travel.
Especially when the treatment liquid is chemically active, such as an etchant, a stripping solution a developing solution or the like, but also in instances in which it is merely a rinsing liquid, possibly with some minerals therein, it is desirable to prevent the uneven accumulation of liquid on surfaces of articles. Most particularly, for example, when the articles are generally horizontally disposed and oriented, it is undesirable to have puddles of the treatment liquid forming on an upper surface thereof. Even without such puddles, it is desirable that the treatment liquid be substantially evenly disposed along the surfaces of articles being treated, whether from above or below, and whether the articles are horizontally carried, or oriented, or not.
Thus, to facilitate the evenness of application of treatment liquid, and to prevent the aforesaid puddling, it is known in the art to vary the angle of application of treatment liquid from orifices, by pivoting the nozzles, floodbars, spray heads or the like, as articles pass thereby along their path of travel, to provide some variation in the angle of application of treatment liquid, and hence some variation in the angle of impingement of treatment liquid onto surfaces of printed circuit boards, articles or the like. This variation of angular orientation by pivoting or arcuately moving the angle of liquid application tends to reduce opportunity for puddling, tends to apply the liquid more evenly, eliminating dry spots, and tends to chase accumulations of liquid from the articles.